I recently bought a DC regulator (power supply and tester.) It is a 15V and 2A power supply with voltage fixed to 1.5V, 3.6V, 4.8V, 6.0V, 7.2V direct output of the sub-grade and the current is adjustable from 0.6 to 2A. It also has potentiometers for fine voltage and coarse voltage, but I do not get any difference when it is connected to a multimeter. I rotated the coarse and fine potentiometers but the output didn't change, not even when I connect it to other electronics.

Is it possible to change the potentiometer from fixed to variable?

Fixed potentiometer


enter image description here

  • \$\begingroup\$ This question would need much more detail to be answerable. It kind of looks like maybe there's a selector switch somewhere which would select which one of those combinations would be active, and maybe that is not set for the one you were adjusting? \$\endgroup\$ Sep 24, 2020 at 14:43
  • 1
    \$\begingroup\$ I believe you have to put you voltage selector knob to the last position. Not sure waht you get now that you have tweaked calibration pots! \$\endgroup\$ Sep 24, 2020 at 15:34
  • \$\begingroup\$ Where are you measuring to get no difference? They are three pin devices, make sure you're probing the correct pin. \$\endgroup\$
    – Puffafish
    Sep 25, 2020 at 10:46

1 Answer 1


To the right of the current knob is a knob to select voltage. It is set to 6V in your picture. Rotate that knob so that it points to "3-15" or whatever the right most marking is. That is the variable voltage setting.

With the selector knob set to the variable range, the coarse and fine voltage knobs will set the output voltage.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.